Nonlinear absorption temporal dynamics of Fe-doped GaInAs/InP multiple quantum wells

Abstract

Articles you may be interested in290 fs switching time of Fe-doped quantum well saturable absorbers in a microcavity in 1.55 μ m range Appl. Phys. Lett. 85, 5926 (2004); 10.1063/1.1804239 Ultrashort, nonlinear, optical time response of Fe-doped InGaAs/InP multiple quantum wells in 1.55-μm range Appl. Phys. Lett. 82, 1670 (2003); 10.1063/1.1557333 High-speed 1.55 μm Fe-doped multiple-quantum-well saturable absorber on InP Appl. Phys. Lett. 78, 4065 (2001); 10.1063/1.1381410 Time-frequency spectroscopy of an InGaAs/InP quantum-well exciton Bragg reflector Appl. Phys. Lett. 74, 2569 (1999); 10.1063/1.123900Carrier lifetime and exciton saturation in a strain-balanced InGaAs/InAsP multiple quantum well GaInAs/InP multiple quantum wells ͑MQWs͒ are used as saturable absorbers for all-optical signal regeneration at a 1.55-m wavelength. These MQWs are doped during their growth by molecular-beam epitaxy with Fe to improve their temporal response. The present work develops a theoretical description of the carrier recombination dynamics in these MQWs. Temporal evolution of the populations of excitons, holes, electrons, and iron traps is determined by coupled evolution equations. The model describes the optical temporal nonlinearity of the saturable absorbers near the excitonic peak transition. Furthermore, pump-probe experiments have been performed to measure the recovery time of these structures having different Fe doping concentrations. A good agreement between the experimental measurements and the model predictions of the optical temporal behaviors of the saturable absorbers is obtained. The control of the recovery time ͑nanoseconds to picoseconds͒ with the Fe traps in a large concentration range (10 15 to 10 19 cm Ϫ3 ) is particularly well highlighted by this model. The Fe doping concentration prescribed to reach a targeted fast recovery time is predicted with good accuracy by the model, which leads us to propose an attractive way to design ultra-high-speed, all-optical signal regenerators based on saturable absorbers.

A direct comparison of single-walled carbon nanotubes and quantum-wells based subpicosecond saturable absorbers for all optical signal regeneration at 1.55 μm

“…The decrease in decay time is attributed to the relaxation mechanism between neutral Fe state in its Fe 3+ configuration in wells with photogenerated electrons and holes. 12,13 SWNT used in this work were grown using a modified gas phase process ͑HiPCO͒, and were supplied by Carbon Nanotechnologies Inc. The raw material was initially dispersed and sonicated in N-methyl pyrrolidone.…”

Analysis of thermal limitations in high-speed microcavity saturable absorber all-optical switching gates

“…MQW-SAs typically have a rather long recovery time (in the nanosecond range). In order to significantly decrease the response time of these materials and to make them compatible with high bit rate operation, capture and recombination centers must be introduced during or after crystal growth by means of low-temperature molecular beam epitaxy [15], ion implantation [16], heavy ion irradiation [17], or Be or Fe doping [18], [19]. These methods of damage creation have been reported to provide recovery times in the sub-picosecond range [20], [21].…”

All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity

“…To significantly decrease the response time of these materials, capture and recombination centers can be introduced during or after crystal growth by means of low-temperature molecular beam epitaxy, 4 highenergy ion implantation, 5 or Be or Fe doping. 6,7 These methods of damage creation have been reported to provide recovery times as short as a few pi-coseconds in an InP-based semiconductor. 5 The combination of heavy-ion irradiation with a silver-based backmirror compact microcavity has proved to be a convenient solution to making efficient optical gates.…”